A047738 Earliest sequence of 4 consecutive economical numbers.

179210312, 179210313, 179210314, 179210315

Offset

1,1

Links

Table of n, a(n) for n=1..4.

Tanya Khovanova, Non Recursions

J.-M. De Koninck and F. Luca, On strings of consecutive economical numbers of arbitrary length, Integers: Electronic Journal of Combinatorial Number Theory 5, (2005), #A5.

Eric Weisstein's World of Mathematics, Economical Number

Example

179210312 = 2^3* 4733^2; 9 digits in 179219312, 7 digits in its prime factorization, 7 < 9, so that number is economical.

Crossrefs

Cf. A046759.

Sequence in context: A213966 A206520 A127955 * A079323 A228760 A204529

Adjacent sequences: A047735 A047736 A047737 * A047739 A047740 A047741

Keyword

fini,full,nonn,base

Author

Carlos Rivera

Status

approved